1. Field of the Invention
The present invention relates to a coated magnetic recording media such as a magnetic tape, a magnetic sheet or a magnetic disc used for audio equipment, video equipment, computer and so on.
2. Description of the Related Art
Magnetic recording media requires a flat surface, to avoid that reproduction output drops since spacing loss and a noise is generated by irregularities. Consequently, magnetic recording media for high density recording requires an extremely flat surface.
However, the flat surface causes a substantial contact area between the magnetic layer and each of parts in a recording-reproducing apparatus (id. tape recorder) to increase. The increased contact area enlarges a frictional force between the magnetic layer and the parts. Moreover, the increased contact area causes sticking of the magnetic head, which has a flat surface, with the magnetic layer to occur easily. That is, the flatter the surface is, the faster the magnetic layer wears and the more easily exfoliation occurs.
Consequently, to improve durability of the medium with a flat surface, conventionally, lubricant such as higher fatty acid or higher fatty acid ester is added into the magnetic layer or is coated on the surface of the magnetic layer, thereby lowing frictional force between the magnetic recording media and the magnetic head or the like. There is also a case that hard fine particles called for abrasive or filler.
However, only by applying durability improvement technology used so far, it is impossible to obtain magnetic recording media capable of keeping high durability under required severe environment (such as environment of low temperature and low humidity or high temperature and high humidity, environment of a high relative speed to a magnetic head).